9,806 research outputs found
Considering Convergence: A Policy Dialogue About Behavioral Genetics, Neuroscience, and Law
Garland and Frankel issue a call for scientists, lawyers, courts and lawmakers to begin a critical dialogue about the implications of scientific discoveries and technological advances in criminal law, behavioral genetics and neuroscience
Subinhibitory concentrations of trimethoprim and sulfamethoxazole prevent biofilm formation by Acinetobacter baumannii through inhibition of Csu pilus expression
ABSTRACT
Acinetobacter baumannii
is emerging as a multidrug-resistant nosocomial pathogen of increasing threat to human health worldwide. Pili are important bacterial virulence factors, playing a role in attachment to host cells and biofilm formation. The Csu pilus, which is assembled via the chaperone-usher secretion system, has been studied in
A. baumannii
ATCC 19606. Here we show that, in opposition to previous reports, the common laboratory strain ATCC 17978 produces Csu pili. We found that, although ATCC 17978 was resistant to sulfamethoxazole (Smx) and trimethoprim (Tmp), subinhibitory concentrations of these antibiotics abolished the expression of Csu and consequently produced a dramatic reduction in biofilm formation by ATCC 17978. Smx and Tmp acted synergistically to inhibit the enzymatic systems involved in the bacterial synthesis of tetrahydrofolate (THF), which is required for the synthesis of nucleotides. The effects of these antibiotics were partially relieved by exogenous THF addition, indicating that Smx and Tmp turn off Csu assembly by inducing folate stress. We propose that, for
Acinetobacter
, nanomolar concentrations of Smx and Tmp represent a “danger signal.” In response to this signal, Csu expression is repressed, allowing biofilm dispersal and escape from potentially inhibitory concentrations of antibiotics. The roles of antibiotics as signaling molecules are being increasingly acknowledged, with clear implications for both the treatment of bacterial diseases and the understanding of complex microbial interactions in the environment.
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Structurally Embedded Electrical Systems Using Ultrasonic Consolidation (UC)
Current research has demonstrated the use of Ultrasonic Consolidation (UC) to embed
several USB-based sensors into aluminum, and is working toward embedding suites of
sensors, heaters and other devices, connected via USB hubs, which can be monitored and
controlled using an embedded USB capable processor. Additionally, the research has
shown that electronics can be embedded at room temperature, but with some inter-layer
delamination between the ultrasonically bonded aluminum layers. Embedding sensors
and electronics at 300o
F to overcome the delamination issues resulted in optimal
bonding, and the sensors used thus far have functioned normally. Future investigation
will explore other UC parameter combinations to ascertain the quality of embedding at
lower temperatures.Mechanical Engineerin
Three months journeying of a Hawaiian monk seal
Hawaiian monk seals (Monachus schauinslandi) are endemic to the Hawaiian
Islands and are the most endangered species of marine mammal that lives
entirely within the jurisdiction of the United States. The species numbers
around 1300 and has been declining owing, among other things, to poor juvenile
survival which is evidently related to poor foraging success. Consequently,
data have been collected recently on the foraging habitats, movements, and
behaviors of monk seals throughout the Northwestern and main Hawaiian Islands.
Our work here is directed to exploring a data set located in a relatively
shallow offshore submerged bank (Penguin Bank) in our search of a model for a
seal's journey. The work ends by fitting a stochastic differential equation
(SDE) that mimics some aspects of the behavior of seals by working with
location data collected for one seal. The SDE is found by developing a time
varying potential function with two points of attraction. The times of location
are irregularly spaced and not close together geographically, leading to some
difficulties of interpretation. Synthetic plots generated using the model are
employed to assess its reasonableness spatially and temporally. One aspect is
that the animal stays mainly southwest of Molokai. The work led to the
estimation of the lengths and locations of the seal's foraging trips.Comment: Published in at http://dx.doi.org/10.1214/193940307000000473 the IMS
Collections (http://www.imstat.org/publications/imscollections.htm) by the
Institute of Mathematical Statistics (http://www.imstat.org
Municipal Antitrust Immunity after \u3ci\u3eCity of Columbia v. Omni Outdoor Advertising, Inc.\u3c/i\u3e, 111 S. Ct. 1344 (1991)
For most of this century, states and municipalities were immune from liability for anticompetitive action. However, in City of Lafayette v. Louisiana Power & Light Co., the Supreme Court sharply limited antitrust immunity for municipalities. The Lafayette Court held that municipal immunity only applied to municipalities following a clearly articulated state policy. In City of Columbia v. Omni Outdoor Advertising, Inc, the Supreme Court has expanded the immunity available to municipalities by requiring only that a municipality\u27s actions be a foreseeable result of a specific grant of state authority. This Note examines the history of municipal immunity and the Omni ruling. The Note argues that the foreseeability test is inadequate because it violates federalism principles and treats home rule municipalities inequitably. The Note concludes that the Omni rule should be broadened to protect home rule municipalities
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